1. Field of the Invention
The present invention relates to a substrate processing apparatus and a method of manufacturing a semiconductor device.
2. Description of the Related Art
Recently, there has been a tendency to manufacture semiconductor devices such as flash memories in a highly integrated manner. Thus, pattern sizes of semiconductor devices are becoming finer and finer. To form such a fine pattern, a predetermined treatment process, such as an oxidation process or a nitridation process, may be performed on a substrate as a process included in a semiconductor device manufacturing process.
As one method of forming such a pattern, there is a process of forming a groove between circuits and forming a liner film or wires in the groove. Such grooves are being configured to have higher aspect ratios as pattern sizes become finer and finer.
To form the liner film and the like, it is required to form a film having high step coverage so that the film has a uniform film thickness on an upper side surface, a middle side surface, a lower side surface and a bottom portion of the groove. By forming the film having high step coverage, a semiconductor device may have uniform characteristics between grooves, thereby suppressing a deviation in the characteristics of the semiconductor device.
There have been attempts to process a groove having a high aspect ratio by heating a gas or converting the gas into a plasma state, but a film having high step coverage is difficult to form.
As a method of forming such a film, an alternate supply method of alternately supplying at least two types of process gases and reacting the supplied gases together to form a film has been introduced. In the alternate supply method, a source gas and a reactive gas are reacted on a surface of a substrate, but a purging process is preferably performed between gas supply processes to remove remnant gases while the gases are supplied so that the source gas and the reactive gas may not react with each other on locations other than the surface of the substrate.
Since the characteristics of a semiconductor device on a surface of a substrate need to be uniformized to improve the product yield of the semiconductor device, a gas is evenly supplied within a plane of the substrate when a thin film is formed. To this end, a single-wafer apparatus capable of evenly supplying a gas onto a surface of the substrate to be processed has been developed. In the single-wafer apparatus, for example, a shower head with a buffer space is installed on the substrate to supply a gas onto the substrate more evenly.